Electron-discharge apparatus



Dec. 14 1926. 1,610,783

A. W. HULL ELECTRON DISCHARGE APPARATUS Filed Dec. 18, 1920 J Invehtor-z "gand metho s of'operatin Patented Dec. 14, 1926. 7

UNITED STATES PATENT OFFICE.

.ALIBEB'I' W. HULL, OF SCHENEGI'ADY, YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION 01' NEW YORK. A

ELECTRON-DISCHARGE APPWTUB.

a n anonaied December 15, 1920. sex-mm; 4am.

M present invention relates to the use of eliactron discharge apparatusof the well known'vacuum tube type, and the applica-' tion of suchapparatus to various uses such as am lification of electric currents orthe detection of radio signals. I I

An object of my invention is to provide new and im rovedcircuitorganizations for such v ap aratus which are more efficient t an thoseieretofore employed. I 7

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims. My inventionitself, however; both as to its operation together with further ob ectsand advantages thereof will best be un erstood by reference to thefollowing description taken in connection' with the accompanying drawingin which Fig. 1 shows diagrammatically a cirorganization and method 0cuit arrangement 'which may be used for the amplification ofvariablecurrents, .particularly of audio frequency. Fig. 2 shows asimilar'circuit arrangement for the relaying or amdplification of radiofrequency currents, an Fig; 3 shows acirciut arrange-' ment which maybeemployed as a detector of radio signals. i

As indicated in the drawings, I employ an electron discharge device 1having the usual l0 the otential of the cathode 2 and anode 3,

electron emitting cathode 2, anode 3, a third or grid electrode 4, and agrid or discharge controlling electrode 5.

The direct current source 6 which is connected in the plate or anodecircuit between cathode 2 and anode 3 furnishes the current for theoperation of the device. By means of this source a potential may also beap lied to the grid electrode 4 which is interme late the esiredreduction in potential being obtained by the use of a. potentiometer 7.The current to be plified is im ressed upon the grid circuit betweencatho e 2 and grid 5 by means ofa transformer 8. The amplified currentin the plate circuit, if of'audio frequency, may be impressed by meansof the transformer 9 u on the circuit of a telehone receiver. 10 or thepurpose of producing an audible indication of the amplified currentflowing in the plate circuit. In case the current to be amplified is notof audible frequency any other suitable form of indicating device may beassociated with preferab be emittedfrom the grid electrode 4 to pro ducea negative resistancecharacteristic in the circuit between cathode 2.and grid electrode 4; When operated in this way the variation-in, thepotential ofthe 'rid 5 will produce a high am lification of t e currentflowing in the circu thetween cathode 2 and grid 4 by reason of thenegative resistance characteristic of this circuit. There will at 3 thesame time be produced a corresponding complementary chan e in thecurrent in the circuit between catho e 2 and anode 3. This circuit willnot possess a negative resistance characteristic over the usualoperatingrange and therefore will be stable in itso eration.

In order to produce a high degree 0 amplification alpositive resistance18 which should negative resistance inthe circuit etween the cathode 2and id electrode 4. is inserted in that-circuit. have indicated the useof a single source 6 for obtaining the potential necessary forthe'operation of the device, but separate sources may be employed fortheapplication of the potentials to the two electrodes 3 and 4 in caseit is not convenient to obtain the'desired potentials from a sin issource. v

In he arrangement of Fig. 2, I have indicated a murce 12 of radiofrequency current which is amplified by the system and be approximatelye ual to the i a plied to the transmitting antenna 13 for t etransmission of radio signals.

In the arrangement of 1g. 3 I have indicated the use of an electrondischar e device-as a detector of radio signals. 11 this case thesignals to be detected which are received by the antenna 14 are. imressed uponthe usual resonant idcircuit I5, this grid circuit beingprovi ed with theusual stopping condenser 16 and grid leak 17.

In any of the cases illustrated the device may be operated as a negativeresistance device 1n accordance with the methods of operation describedin the paper entitled The Dynatron published by me in the Proceedings ofthe Institute of Radio Engineers for 1918 at page 5.

In case itis not desired to employ the negative resistancecharacteristic of the device it may however, be employed in the samemanner as the usual three-electrode device. In this case the gridelectrode 4 should be maintained at a ositive potential intermediate thepotentia s of cathode 2 and anodefi, The desired potential for theoperation of the grid 4 may in this case be obtained either by means ofthe potentiometer 7 of F; 1 and 2 or by. va ng the resistance 18 one asindicated in ig. 3. In the operation of the usual three-electrodedevices it has been foundthat there is a marked tendency for theroduction of undesired high frequency oscillations by reason of thecapacity between the dischar e controlling grid and the anode. The use 0the extra grld electrode 4 be tween 'the discharge controlling grid andthe anode,'however, screens the two electrodes in such a way that thistendency s reduced. In this case the resistance18 is preferably shuntedby a condenser 11, which a will permit the alternating component of thecurrent flowing to grid electrode 4 around the resistance 18.

The capacity eifect between IE1 and .anode for athree electrode device aso great- 2/ reduces the ossible amplification of the vice when ra l0frequencies are employed.

' The use of the extra grid electrode 4 reduces the capaci eflr'ect insuch cases and'permits a big 1 degree of amplification with radiofrequencies.

4 In the usual threeelectrode device, a high plate impedance, which isdesirable for operation, can be obtained only at the sacrifice of gridcontrol so that in Ipractice it. has been found best to make the p ateimpedance between 10,000 and 100,000 ohms. The use of the extra gridelectrode in the manner described, however, screens the cathode from theeffect of late voltage, thereby maki'n it possible to ave a very highplate 'impe ance without sacrificing grid control and thereby greatlyincreasing the amplification. While I have shown and described onlythree circuit arrangements in which my invention is employs it will beapparent that my invention is by no means limited to the exact form ofapparatus or the precise circuit connections indicated, as manmodifications, both in the apparatus use as well as in the circuitconnections, may be made without departing from the scope of myinvention as set forth in the ap ended claims.

What I claim as new and esire to secure byLetters Patent of the UnitedStates, is,-

1. An electron discharge device com rising an electron emittin cathodeand at east two other electrodes enc osed in an evacuated receptacle,and sources of potential applied 2. An'electron discharge comprising anelectronemitting cathode, an anode and a grid electrode which isinterposed between cathode-and anode, a source of potential formaintaining the anode at a positive potential with respect to thecathode, and means for maintaining the id electrode at a potential which1s interme 'ate the potentials of cathode and anode, the potentials ofthe anode and grid electrode being so chosen that the n current. betweencathode and grid electrode Wlll, over a defimte working range ofpotential vary inversely as the (potential difierence between cathodeand gri 3. An electron dischar device comprisin an electron emitting cat1ode,an anodean a grid electrode interposed between cathode and anode,means for impressing a constant positive potential upon said anode,means for impressing a positive potential upon the grid electrode ofsuch a value as to produce an emission of secondary electrons from saidgrid electrode, the potentials applied to said electrodes being of suchvalues that the device will have a ne ative resistance characteristicbetween cathode and grid electrode.

4. The method of operating an electron discharge device comprising an telectron emitting cathode, an anode, and a third electrode interposedbetween cathode and anodewhich' consists in'applying a constant positivepotential to the :inode and applying a positive potential to the thirdelectrode of such a, value as to produce an emission of secondaryelectrons therefrom sufficient to give the device a negative resistancecharacteristic.

5. The method of operating an electron discharge device comprising anelectron emitting cathode, an anode and a third electrode betweencathode and anode which consists in applying a constant positivepotential to the anode and applying a positive potential to the thirdelectrode of such a value as to give the device a negative resistancecharacteristic.

6. An electron discharge device comprising an electron emittmg cathode,an anode and two grid electrodes enclosed in an evacuated receptacle, asource of potential for maintaining the \anode at a positive otentialwith respect to the cathode, means or maintaining one of the gridelectrodes which is interposed between cathode and anode at a potentialwhich is intermediate nemfras the potentials of the cathode andanode,-the

potentials of the anode and grid electrode being so chosen that thecurrent between cathode and grid electrode will, over a def: initeworking range of potential vary nversely as the Jotential differencebetween and two grid electrodes interposed between cathode and anode, asource 0 potential for maintaining the anode at a positive potentialwitlr respect to the cathode, means for maintaining the rid electrodenearest the.

anode at a potential intermediate the potentials of the cathode andanode, the potentials of the anode and said grid electrode being sochosen that secondary electrons will be emitted from the grid insufl'icient amount to give the device a negative resistancecharacteristic between cathode and said grid electrode, and means forvarying the potential of the second gridto var the current. flow betweencathode and ano e.

8. The method of operating an electron discharge device having anelectron emitting cathode, an anode and two rids enclosed in anevacuated receptacle, at least one of said grids being interposedbetween cathode and anode, which consists in maintaining the anode andgrid electrode nearest the anode at such potentials with respect to thecathode that a sufficient flow of secondaryelectrons.

from grid electrode to anode will be pro duced to give the device anegative resistance characteristic between cathode and grid electrode,and varying the potential of the second grid electrode and therebyvarying the current flow between cathode and anode.

'9. The method of operating an electron discharge device having anelectron emitting cathode, an anode and two grid electrodes interposedbetween cathode and anode which consists in maintaining the anode angrid electrode nearest the'anode at such potentials with respect to thecathode that the device will have a negative resistance characteristicbetween cathode and said grid electrode, and varying the potential ofthe grid electrode nearest the cathode and thereby varying the currentflow between cathode and anode.

10. An electron discharge device comprising an electron emittingcathode, an anode, a third electrode and a discharge controlling member,of means, for supplying adefinite positive potential to said anode,means for supplying a lower positive potential to the third electrode ofsuch a value as to give the device a negative resistance characteristicbetween cathode and third electrode, means for applying a variablepotential to the dischar 0 controlliifig member to vary the cur rentetween cathode and anode, and means associated with the circuit betweencathode and anode for producing an indication of the current-'variationsin that circuit.

11. An electron discharge device comprising an electron emittingcathode, an anode and two grid electrodes interposed between cathode andanode, oi means for supplying a definite positive potential to saidanode, means for supplying a vlower positive potential to the gridelectrode nearest the anode of such a value as to give the device anegative-resistance characteristic between cathode and "rid electrode,means for applying a variable potential to the id electrode nearest thecathode'to vary t 1e current between cathode and anode, and meansassociated with the circuit between cathode and anode for producing anindication of the current variations in that circuit.

12. The method of operating an electron discharge device comprising anelectron emitting cathode, ananode, a third electrode and a dischargecontrolling member which consists in producing an emission of secondaryelectrons from the third electrode sufiicientto give the device anegative resistance characteristic between cathode and third electrode,applying a variable potential to the discharge controlling member tovary the current between cathode and anode and producing a desiredindication of the current changes between cathode and anode.

13. The method of operating an electron discharge device comprising anelectron emittin cathode, an anode and two grid electrotias interposedbetween cathode and anode, which consists in producing an emission ofsecondary electrons from the grid electrode nearest the anode suificientto give the device a negative resistance characteristic between cathodeand said id electrode applying a variable potentia to the grid electrodenearest the cathode to vary the current between cathode and anode andproducing a desired indication of the current changes between cathodeand anode.

14. In a system for detectin radio signals, the combination of an eectron discharge device having an electron emitting cathode, an anode,and two grid electrodes enclosed in an evacuated receptacle, a sourceofpotential for maintaining this anode at a ositive potential withrespect to the cath o e, means for maintaining one of the gridelectrodes which is interposed between cathode and anode at a potentialintermediate the potentials of the cathode and anode, the potentials ofanode and grid electrode being so chosen that the current betweencathode and grid electrode will, over a definite working range ofotential vary inversely as the potential di erence between cathode andgrid electrode, means for supplying the redio signals to be detected tothe second grid to vary the current flow between cathode and anode inaccordance with the signals cathode and anode, to detect radio signalswhich consists in maintaining the anode and grid electrode nearest theanode at such po tenlials with respect to the cathode-that a sufiicientflow of secondar electrons from grid electrode to anode wi l be producedto give the device a negative resistance characteristic between cathodeand grid electrode, supplying the signals to be detected to the secondgrid electrode and thereby varying the current flow between cathode andanode in accordance with the signals and producing a desired indicationof the signal ing current flowing between cathode and anode.

16. Means for amplifying variable electric currents comprising anelectron dis charge device having an electron emitting cathode, an anodeand two grid electrodes enclosed'in an evacuated receptacle, a source ofpotential for maintaining the anode at a positive potential with respectto the oathode, means for maintaining one of the grid electrodes whichis interposed between cath' ode and anode at a otential which isintermediate the potentials of the cathode and anode, the potentials ofcathode and grid electrode being so chosen that the current betweencathode and grid electrode will over a definite working range ofpotentiai vary inversely as the otential difference between cathode andgrid electrode, a circuit between cathode and second grid and means forsupplying the current to be amplified to said circuit to vary thecurrent flow between cathode and anode in accordance with the current tobe amplified.

17. The method of operating an electron discharge device having anelectron emitting cathode, an anode and two grid electrodes inierposedbetween cathode and anode to amplify a variable electric current whichconsists in maintaining the anode and grid electrode nearest the anodeat such otentiais with respect to the cathode that t e device will havea ne alive resistance characteristic between cat ode and said gridelectrode, and supplying the current to be amplified to a circuitbetween the cathode and the grid electrodenearest the cathode andthereby varying the current flow between cathode andanode in accordancewith the current to be amplified.

In witness whereof, I have hereunto set my hand this 17th day ofDecember, 1920.

ALBERT W. HULL.

dio signals to be detected to the second grid to vary the current flowbetween cathode and anode in accordance with the signals and meansassociated with the circuit between cathode and anode for reducing adesired indication of the signa ing current in that circuit.

15. The method of operating an electron discharge device having anelectron emitting caihode, an anode and two grids enelosed in anevacuated receptacle at least one of said grids being interposed betweencathode and anode, to detect radio signals which consists in maintainingthe anode and grid electrode nearest the anode at such potentials withrespect to the cathode-that a sufiicient flow of secondary electronsfrom grid electrode to anode will be produced to give the device anegative resistance characteristic between cathode and grid electrode,suppl ing the signals to be detected to the secon grid electrode andthereby varying the current flow between cathode and anode in accordancewith the signals and producing a desired indication of the signalode,means for maintaining one of the grid electrodes which is interposedbetween cathode and anode at a potential which is intermediate thepotentials of the cathode and anode, the potentials of cathode and gridelectrode being so chosen that the current between cathode and gridelectrode will, over a definite working range of potential varyinversely as the otential difference between cathode and gri electrode,a circuit between cathode and second grid and means for supplying thecurrent to be amplified to said circuit to vary the current flow betweencathode and anode in accordance with the current to be amplified.

17. The method of operating an electron discharge device having anelectron emitting catl1ode, an anode and two grid electrodes inierposedbetween cathode and anode to amplify a variable electric current whichconsists in maintaining the anode and grid electrode nearest the anodeat such otentials with respect to the cathode that t e device will havea negative resistance characteristic between cathode and'said grid electrade, and supplying the current to be amplitied to a circuit betweenthe cathode and the grid electrode nearest the cathode and therebyvarying the current flow between cathode andanode in accordance with thecurrent to be amplified. p

In witness whereof, I have hereunto set my hand this 17th day ofDecember, 1920.

ALBERT W. HULL.

Certificate of Correction. It is hereby certified that in Letters PatentNo. 1,610,783, ranted December 14,

1926, upon the ap improvement in lication of Albert W. Hull, of Schenecty, New York, for an lectron-Discharge Apparatus, an error appears 111the printed specification requiring correction as follows: Page 2, line76, claim 2, after the word dischar e insert the word device; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent ce.

Signed and sealed th s lstday of February, A. D. 1927.

M. J. MOORE, Afifing Oomvisaiomr of Patmta.

Certificate of Correction.

It is hereby certified that, in Letters Patent No. 1,610,783, qrantedDecember 14, 1926, upon the ap vlicatrion of Albert W. Hull, ofSchenectmf New York, f or an improvement in llectron-l)ischargeApparatus, an error appears in the printed specification requiringcorrection as follows: Page 2, line 76, claim 2, after the worddischarge insert; the word device; and that the said Letters Patentshould be read with this correction therein that the same may conform tothe record of the case in the Patent 0 fice.

Signed and sealed th s 1st. day of February, A. D. 1927.

[mm] M. J. MOORE,

Afdting Umnmdssiomr of Patents.

